Bottom Line:
Using various methods, we confirmed that GPR39 marked a specific cell population at the opening of the SG and colocalised with the SG stem cell marker Blimp1.Although it was dispensable for skin development and homeostasis, GPR39 contributed positively to skin wound healing: its loss led to a delay in wound healing during the intermediate stage.The present study reveals a novel role of GPR39 in both dermatology and stem cell biology that has not been previously recognised.

ABSTRACTG protein-coupled receptors (GPCRs) mediate multiple key biological processes in the body. The orphan receptor GPR39 has been reported to be involved in various pathophysiological events. However, the function of GPR39 in skin biology remains unknown. Using a genetically engineered mouse strain in which lacZ expression faithfully replaced endogenous Gpr39 expression, we discovered a unique expression pattern of Gpr39 in the sebaceous gland (SG). Using various methods, we confirmed that GPR39 marked a specific cell population at the opening of the SG and colocalised with the SG stem cell marker Blimp1. Further investigations showed that GPR39 was spatiotemporally expressed during skin wound repair. Although it was dispensable for skin development and homeostasis, GPR39 contributed positively to skin wound healing: its loss led to a delay in wound healing during the intermediate stage. The present study reveals a novel role of GPR39 in both dermatology and stem cell biology that has not been previously recognised.

f4: Wound healing assay in Gpr39+/+ and Gpr39−/− mice.(a) Images of wound areas in Gpr39+/+ and Gpr39−/− mice on different days after wounding, with the same magnification. (b) Statistical analysis of wound size change in both Gpr39+/+ and Gpr39−/− mice. The P value for each comparison is labelled above the columns. The data present the means ± SEM, and the asterisks indicate statistically significant differences with a P value < 0.05.

Mentions:
The intriguing expression pattern of GPR39 at the wound site implied a function of GPR39 in wound repair. To assess whether GPR39 was involved in skin wound repair, we made uniform skin wounds (1/8-inch, circular, full-thickness cutaneous wounds) in 7- to 8-week-old Gpr39+/+ mice and in Gpr39−/− mice in which both Gpr39 alleles had been replaced by lacZ sequences. We monitored and measured the wound size from D0 to D12 post wounding. Wound closure was slower in the Gpr39−/− mice than in their wild-type siblings (Fig. 4a). A statistical analysis of wound size change also indicated a significant delay in the wound closure rate in the Gpr39−/− mice on D6 and D8 (Fig. 4b), indicating that GPR39 contributes to skin wound healing.

f4: Wound healing assay in Gpr39+/+ and Gpr39−/− mice.(a) Images of wound areas in Gpr39+/+ and Gpr39−/− mice on different days after wounding, with the same magnification. (b) Statistical analysis of wound size change in both Gpr39+/+ and Gpr39−/− mice. The P value for each comparison is labelled above the columns. The data present the means ± SEM, and the asterisks indicate statistically significant differences with a P value < 0.05.

Mentions:
The intriguing expression pattern of GPR39 at the wound site implied a function of GPR39 in wound repair. To assess whether GPR39 was involved in skin wound repair, we made uniform skin wounds (1/8-inch, circular, full-thickness cutaneous wounds) in 7- to 8-week-old Gpr39+/+ mice and in Gpr39−/− mice in which both Gpr39 alleles had been replaced by lacZ sequences. We monitored and measured the wound size from D0 to D12 post wounding. Wound closure was slower in the Gpr39−/− mice than in their wild-type siblings (Fig. 4a). A statistical analysis of wound size change also indicated a significant delay in the wound closure rate in the Gpr39−/− mice on D6 and D8 (Fig. 4b), indicating that GPR39 contributes to skin wound healing.

Bottom Line:
Using various methods, we confirmed that GPR39 marked a specific cell population at the opening of the SG and colocalised with the SG stem cell marker Blimp1.Although it was dispensable for skin development and homeostasis, GPR39 contributed positively to skin wound healing: its loss led to a delay in wound healing during the intermediate stage.The present study reveals a novel role of GPR39 in both dermatology and stem cell biology that has not been previously recognised.

ABSTRACTG protein-coupled receptors (GPCRs) mediate multiple key biological processes in the body. The orphan receptor GPR39 has been reported to be involved in various pathophysiological events. However, the function of GPR39 in skin biology remains unknown. Using a genetically engineered mouse strain in which lacZ expression faithfully replaced endogenous Gpr39 expression, we discovered a unique expression pattern of Gpr39 in the sebaceous gland (SG). Using various methods, we confirmed that GPR39 marked a specific cell population at the opening of the SG and colocalised with the SG stem cell marker Blimp1. Further investigations showed that GPR39 was spatiotemporally expressed during skin wound repair. Although it was dispensable for skin development and homeostasis, GPR39 contributed positively to skin wound healing: its loss led to a delay in wound healing during the intermediate stage. The present study reveals a novel role of GPR39 in both dermatology and stem cell biology that has not been previously recognised.